1. Field of the Invention
This invention relates to apparatus of the heated vacuum rotary vessel type for drying and/or treating powdered, granular or flaked material.
2. Description of the Prior Art
Drying of powdered material under conditions of vacuum or heat is a concept that has long been known in the prior art. Such apparatus usually included a furnace with the powdered material on a static plate and with vacuum applied to the chamber surrounding the plate. This apparatus does not fluidize the material.
Another prior art apparatus included a fine screen supporting a bed of material through which dry air was blown, which fluidized the bed and which air exited through a cloth bag. This apparatus loses or classifies a portion of the material through the bag, cannot get the material drier than the surrounding atmosphere, and does not dry uniformly due to the tendency of the heavier particles to be at the bottom of the mix.
None of the prior art apparatus completely and properly dried the material.
Rotary furnaces which expose the material therein to heat are known, and particularly in the portland cement industry, but are not satisfactory for drying and treatment of many materials and do not operate under controlled atmospheric or vacuum conditions.
The uniform and homogenous drying of powdered, granular or flaked materials under conditions of heat and vacuum as they free fall in a rotating vessel offers advantages not found in the prior art.
The uniform and homogenous processing of material by passing gas over and through powdered, granular, or flaked materials as they free fall in controlled atmospheric conditions and in a gas atmosphere while in a heated or unheated rotating vessel, offers advantages not found in the prior art.
Certain materials such as powdered materials for anhydrous alkali metal batteries, organic and inorganic chemicals, pharmaceutical, biological, metallurgical and nuclear products require uniform and homogenous processing or drying in an environment where there are no contaminants, such as moisture, where drying is controlled and for certain materials processing can advantageously occur while in the apparatus.